Homing arrangement for selector switches



Jan. 6, 1953 G. DEAKIN 2,624,307

HOMING ARRANGEMENT FOR SELECTOR SWITCHES Filed April 2, 1949 4Sheets-Sheet l INVENTOR 65 541. 0 054K IA ATTO R N EY Jan. 6, 1953 e.DEAKIN 2,624,807

HOMING ARRANGEMENT FOR SELECTOR SWITCHES ATTO R N EY Jan. 6, 1953 G.DEAKIN HOMING ARRANGEMENT FOR SELECTOR SWITCHES Filed April 2, 1949 4Sheets-Sheet 3 INVENTOR GERALD PEAK/N ATTO R N EY 2D C: t C fiHl l l l ll l U IHI IHU I IH H NH H H h l l lH l I lH HHl l l l l l l lH lH HH Q QINVENTOR ATTORNEY G. DEAKIN HOMING ARRANGEMENT FOR SELECTOR SWITCHESFiled April 2, 1949 Jan. 6, 1953 Patented Jan. 6, 1953 HOMINGARRANGEMENT FOR SELECTOR SWITCHES Gerald Deakin, New York, N. Y.,assignor to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Application April 2, 1949, Serial No.85,186

9 Claims.

' selector switch with two sets of brushes engaging rows of terminalsarranged in sets and with automatic means to connect an operatingcircuit to the brushes engaging one set of terminals when the carriageis moving in one direction and to the brushes engaging another set ofterminals'when the carriage is moved in the opposite direction.

Another object of the invention is to provide a signalling device foruse when a selector switch is at rest in determining which direction thecarriage was moving when it came to rest, and also an indicating meansfor identifying the terminal pins upon which the switch has stopped.

Briefly, the invention comprises a selector switch provided with twocontact spring assemblies attached to the frame of the switch. Mechanismmounted on the frame is provided which is engaged by a member attachedto the reciprocating carriage of the switch for operating one of thecontact spring assemblies for controlling the carriage driving mechanismso as to cause it to stop at a predetermined position or predeterminedpositions. .And another mechanism also mounted on the frame is caused tobe moved by the movement of the carriage to operate the other contactspring assembly to transfer the connection of the operating circuit fromone set of brushes to another at the end of each reciprocatory movementof the carriage.

The above mentioned and other features and objects of this invention andthe manner of attaining them will become more apparent, and theinvention itself will be best understood by reference to the followingdescription of an embodiment of the invention taken in conjunction withthe accompanying drawings wherein:

Figure l is a bottom plan view of a complete assembly of the selectorswitch of the invention with the terminals removed and a portion of thebail for operating the homing contacts removed in order to disclosemechanism for changing the connection from one set of brushes toanother;

Figure 2 is an elevational view of the switch shown in Figure 1;

Figure 3 is a bottom plan view, greatly enlarged, of a portion of theswitch of Figure 1 showing the 2 mechanism for operating the homingcontacts and for transferring the connections between the two sets ofbrushes, the carriage being shown at the left end of its movement;

Figure 4 is a similar bottom plan view of the mechanism showing thecarriage at the right end of its movement;

Figures 5, 6, 7 and 8 are sectional end views of the switch taken on thelines 5-5, 66, '|--1, and 8-8 respectively of Figure l, with Figures 6and 8 showing the bail slightly rotated.

Where a plurality of selector switches of the type used in thisinvention are connected in a telephone circuit and are multipliedtogether, all the switches not busy may be caused to start when a callis received. It will be apparent that when the desired terminal is nearthe end of the movement of the brush carriage more time will be involvedin reaching it than when such terminal is near the beginning of themovement. By arranging two automatic homing positions one at each end ofthe switch, some of the switches will always be at rest with their brushcarriage at one end, while other switches will be at rest with theirbrush carriages at the opposite end. Therefore, when two switches havingbrush carriages at rest on opposite ends start to find a given terminal,one of those switches will have its brush carriage nearer the terminalthan the other and will therefore arrive at this terminal before theother, and considerable time is thus saved. This is especially true withthe type of switch in which one set of brushes is electrically connectedto a set of terminals while the brushes are mov ing in one direction,and another set of brushes is electrically connected to-another set ofterminals while the brushes are moving in the opposite direction, sincewithout the two homing positions a brush carriage might have to moveclear across the switch and backagain before the second set of brusheswould find a terminal on the second set of terminals.

Referring now more particularly to the drawings, a selector switch hasbeen shown having a frame I, a carriage 2, mounted for reciprocation onsaid frame, and a mechanism 3 for driving the carriage.

, The frame 1 comprises two end brackets 4 and 5 spaced apart by twoparallel guide rods 5 and I and an angle member 8. The rods areconnected between spaced opposed points midway between the ends of thebrackets and may be attached to the brackets in any desirable manner.The angle member 8 is connected between two opposing corners of thebrackets and may have one edge flush with the bracket sides,

the adjacent side parallel to the ends of the v brackets, and the otherside at right angle to the ends towards the center. The angle member maybe attached to portions of the brackets by screws or rivets.

The carriage 2 may comprise a plate 9 having four integral right angleextensions in at the corners thereof, which are secured to fourcylindrical bearings H which slide upon the guide I rods 6 and I, so asto support the plate on the opposite side of said rods from said anglememher for reciprocation parallel to the guide rods.

Any suitable arrangement for lubricating the guide rods as thecylindrical bearings slide thereon may be used, although in thearrangement illustrated I have shown sleeves l2 of felt or other oilsaturable material mounted on the. guide rods between the bearings ofeach pair.

The plate 9 is provided with flanges l3 bent from opposite sides of theplate in a direction opposite to that of thev extensions in to providecorner posts for a brush assembly comprising two sets of brushes [4 and[5 which are insulatedly mounted in any suitable manner so as to bespaced apart in aligned sets, there being four brushes to each set inthe particular switch illustrated. The manner of assembling thesebrushes forms no part of the present invention.

The switch frame and brush mechanism are supported upon a suitable rackIS, a portion of which is illustrated in Figures 1 and 5, which in turn,supports two sets of terminal pins [1 and [8 arranged in parallel rowsso that the brushes engage one pin in each row at a time as the carriagereciprocates. In this arrangement shown there are four rows of terminalplus, one row for each brush of a set.

The driving mechanism 3 for the switch forms no part of the presentinvention and may be any suitable type as, for example, as described inmy copending U. S. application Serial No. 35,202/48, filed June 25,1948, which shows alternately driven gears (not shown) which mesh withtwo rack bars I9 attached to the plate 9 of the carriage 2 between theguide rods 6 and I and moving in a suitable housing including the homingmember 20. Although the mechanism for driving the rack. bars is notshown in detail, it will be understood that it is controlled by a clutchmechanism which includes the flexible driving gear 3a, shown. in Figures1 and 2. The clutch mech-'- anism may be operated electrically and itwill be sufficient for the purpose of this description to state that asuitable circuit is provided for controlling the clutch mechanism whichincludes the contact springs 2| of any suitable contact spring assembly22 mounted upon the angle member between it and the rack bars.

These contact springs are caused to be operated when the carriagereaches a predetermined point in its movement after the release of theswitch, so that the carriage will stop at apredetermined point which maybe called the homing position.

The contact springs 25 are operated by means of a bail 23 which extendsadjacent and substantially parallel to the angle member 8 and ispivotally secured to flanges 2.4. which are bent outwardly from theflange 25' of the angle mem: her 8. The bail 23 comprises a flat barhaving end flanges 25 arranged to be parallel to the flanges 2G to whichthey are pivoted by means of suitable screws 2?. The flat bar of. thebail normally lies parallel to the flange 25 of the angle member 8' butmay be rotated about its pivot in.

- for attaching the rack bars [9 to the a counterclockwise direction, asviewed in Figure 6 to operate the contact springs 2!. To this end an arm28 (see Figure 7) is provided extending from one of the bail end flanges26 on the side of the pivot screw 2] opposite to the fiat portion of thebail. This arm 28 engages a spring finger 29 mounted. on the contactspring assembly 22 and carrying a pair of arms 3% which in turn supportan insulating member 3| which engages the contact springs to make andbreak the. contacts as the spring finger 29 is moved. The tension of thespring finger 29 normally maintains the bail in this position, as shownin Figure 1.

In order to cause rotation of the bail I provide an arm' 32 which isattached to the plate 9 of the carriage at about the center thereof, thearm having a flange 33 for attaching to the carriage and thus beingspaced nearer the guide rod 6 than the guide rod 1 because of the flangearrangement This arm 3'2 may form the means carriage, as indicated.

The arm 32 extends outwardly from the plate 9 to a point beyond theangle member 8 and has attached to it cam members 3% which extend ashort distance on each side of the arm 32' and are adapted to bepositioned adjacent the edge of the nail 23. The bail 23 throughout mostof its length is narrower than it is at the end flanges 26 as clearlyshown in Figures 1, 3 and 4, and the change in width adjacent the endsprovides cam surfaces upon which the cam members 3 attached to the arm32 may ride. As shown, when one of the cam members 3'5; engages a camsurface 35 at its associated end of the bail and the carriage continuesto move towards. the end of the bail, the cam member 34 will cause thebail to rotate to a position shown in Figures 3, 4, 6 and 8', and willthus cause the bailarm 28 to push the spring finger 29 against its owntension, so as to operate the contact springs 2| and cause the centerspring, in the particular switch illustrated, to break its contact withthe lower spring and make its contact with the upper spring. By means ofthe circuit already referred to and illustrated by the wires which areattached to the contact springs, the clutch mechanism controlling themovement of the carriage will be operated to stop the carriage.

In the embodiment shown, I have provided cam surfaces 35 at each end ofthe bailand cam memhere 35' arranged to engage these surfaces, asindicated in Figures 3 and 4, at each end of the carriage movement.Therefore, the carriage will stop under control of its homing? mechanismat each end of its movement. It will be understood however that thehoming position of the switch may be chosen at any desirable point, inwhich 7 case a suitable cam may be provided at that point 3 provided atone end of the switch mechanism leaving room at the other end for asecond contact spring assembly 3? which may be used for translerring thecircuit connections from, the first set of brushes M to the second setof brushes i5 and vice versa when the carriage reaches the-ends ofi tsstroke. This second contact spring assem-- bly 31 carries contactsprings 38 which are connected by means of wires 39 to a circuit whichincludes either of the brushes l4 or the brushes IS in the operation ofthe switch.

The connection to the brushes are made by means of bus bars 40 and 4|which are mounted in spaced relation parallel to the guide rods 5 andand between the guide rods and the brushes by means of insulating plates42 which are mounted on the end brackets 4 and 5 by means of suitablesupports 43 and 44 respectively. Each of these bus bars may be connectedby a wire shown at 45 to the circuit referred to above but which has notbeen otherwise indicated. The brushes l4 and I5 are each provided withcontact members 46 and 41 which engage the bus bars 40 and 4| so as toconnect the brushes thereto. As indicated in the drawing, when thecentral contact spring 38 engages the lower spring, as is shown inFigure 3, the circuit is connected to the brushes i4, whereas if thecenter contact spring 38 engages the upper contact spring, as is shownin Figure 4, the circuit will be connected to the'other set of brushesl5.

' In order to shift the contact springs 38, a spring finger 48 isprovided, somewhat'similar to the spring'finger 29 of the contact springassembly 22. This spring finger 48 is provided with arms 49 at rightangles thereto which support an insulating member 50 for moving thecenter spring 38.

In order to move the finger 48 I provide a flat bar 5| and mount it forreciprocation along the surface of the flange 25 of the angle member 8.To this end I provide slots 52 in the bar 5| and screw the bar 5| to theflange 25 by means of screws 53 passing through plates 54, thus holdingthe bar 5| between the plates 54 and the flange 25 but permittingreciprocating motion of the bar, limited only by the length of theslots. same screws 53 which thus guide the bar 5| in its reciprocatingmovement may be used to secure the contact spring assemblies 22 and 31to the angle member 8 by means of flanged brackets 55 and 56respectively.

The ends of the bar 5| are provided with flanges 5'! and 58 and theseflanges are adapted to be engaged by an extended portion of the arm 32attached to the carriage 2. The length of the bar 5| is such that thearm 32 attached to'the carriage 2 will strike the flanges 51 and 58 justbefore the carriage reaches the end of its stroke. Thus as the carriagemoves towards the right, as viewed in Figure 4, the arm 32 will strikethe flange 51 and move the bar 5| toward the right.

When the carriage moves'to the left the bar will not move until the arm32 strikes'the flange 58, as shown in Figure 3. at which time the bar 5|will be moved from its former position towards the left.

The bar 5| isprovided with a lug 59 adjacent the end near the contactspring assembly 31 and this lug carries a pin 69 which extends at rightangles to the bar adjacent the spring finger 48. The spring finger 48 isbent to form a cam surface 6| which co-operates with the pin 50, so asto move the spring finger 48 against its own tension when the bar 5| ismoved to the right, as in Figure 4, and thus operate the center contactspring 38 to move it into contact with the upper spring, as viewed inthat figure.

When the bar 5| is moved to the left, as shown in Figure 3, the pin 60will ride over the cam surface 6|, so as to permit the spring finger 48to return to normal and the center contact spring 38 in Figure 4, whereit will remain until the car- I riage reaches its left limit ofmovement. Thus the brushes M and I5 are connected in the circuitalternately as the carriage moves from left to right and from right toleft. The selector switch will therefore operate to make contact withthe set of terminal pins I! when the carriage is moving in one directionand with the set of terminal pins l8 when the carriage is moving in theother direction, thus providing twice the number of pins engageable bythe brushes by one sweep of the carriage.

As has been stated, there are four brushes to a set and four rows ofco-operating terminal pins;

' hence in order to make the proper connections I provide four sets ofthe contact springs 38 which are in alignment and are all controlled bythe spring finger 48. Similarly, as many sets as necessary contactsprings 2| may be provided for controlling the homing operation.

' It is desirable when the carriage is stopped with the brushes engaginga particular group of terminals, to be able to identify the terminalswith which contact is made and, at the same time,

the direction of movement of the carriage, so

that it can be readily ascertained which of the I groups of brushes, andtherefore which of the The terminal pins are connected in the circuit.In order to accomplish this, a scale 62 is secured to the angle member 8in any suitable manner as by means of screws 63, the edge of the scalecoming close to the ends of the arm 32 which is decreased in size toform an indicating point 64 which indicates on the edge of the scale theposition of the carriage at any particular instant. The scale may begraduated in any desired way to indicate the numbers of the terminalsinvolved.

In addition to the point 64a slightly larger spring flange 65 may beattached to the end of the arm 32 to provide a more easily discernablesignal to locate the position of the indicating point.

' In order to indicate which direction the carriage was moving before itstopped at any particular location, the flange 51 of the bar 5| may haveits edge toward the scale 62 bent so as to form a signal 66, and thelength of the scale may be such. as.

to hide this signal, as indicated in Figure 3', when the bar 5| is movedto the left, but to disclose'the signal when the bar is moved to theright, 'as' indicated in Figure 4. Thus, the operator has only to glanceat the signal 66 whenever the switch is stopped in some particularposition in order to obtain the desired information. v

It will be seen from the above description that I. have provided aselector switch which includes simple and effective mechanism forcausing a de sired homing action of the carriage when the carriage isnot in actual use and simpleand effective mechanism for transferring thebrush connections as the carriage changes direction. In addition, I haveprovided a simple device for indicating the exact set of terminals withwhich the ratus, it is .to be clearly understood that this descriptionis made only by way of example and not as alimitation to the scope. ofmy invention.

What I claim is:

1. In a selector switch comprising a frame, a plurality of terminalssupported by said frame and arranged in at least two parallel rows, acarriage mounted on said frame for reciprocating movement in a pathparallel to said rows of terminals, brushes carried by said carriage andadapted to engage respectively the terminals of said rows as saidcarriage reciprocates, means for reciprocating said carriage, and anelectrical circuit, the combination of said selector switch with meanscontrolled by the movement of said carriage for connecting said circuitwith one brush when the carriage is moving in one direction and with theother when the carriage is moving in the other direction, saidlast-mentioned means including spring contacts, a member movable intotwo positions and engaging said contacts to connect said circuit to onebrush when said member is in one position and to the other brush whensaid member is in the other position, and means attached to saidcarriage for moving said member into one position at the end of themovement of the carriage in one direction and into the other position atthe end of the movement of the carriage in the other direction.

2. The combination of a selector switch with spring contact meansaccording to claim 1, in which the member is a bar slidably mounted inthe frame parallel to the path of the carriage and having end extensionssubstantially perpendicular to the path of the carriage, and the meansfor moving said member is an arm attached to the carriage and extendingoutwardly to engage said end extensions.

3. The combination of a selector switch with spring contact meansaccording to claim 1, in which the. means for connecting the circuit tothe brushes includes a signal operative to indicate which brush isconnected.

4., The combination of a selector switch with spring contact meansaccording to claim 1, comprising a signal for indicating which positionsaid member is in at. a given instant.

5. The combination of a selector switch with spring contact meansaccording to claim 1, in which the member is a bar slidably mounted inthe frame parallel to the path of the carriage and having end extensionssubstantially perpendicular to the path of the carriage, the means formoving the member is an arm attached to the carriage. and extendingoutwardly to engage said end extensions, and the signal comprises anind-ica attached to one of said extensions and a shield attached to saidframe to cover said indicia when said member is in one of its positions.

6. The combination of a selector switch with spring contact meansaccording to claim 1, in which the means for connecting the circuit tothe brushes includes a signal, operative to indicate which brushes areconnected, and in which an indicating scale is provided mounted on saidframe and an arm is provided on said carriage cooperating with saidscale to indicate the terminals in contact with said brushes when saidcarriage is at rest.

7. In a selector switch comprising a frame, a bank of terminal pinsmounted in said frame in rows arranged in two groups, a carriage mountedon said frame for reciprocation in a path parallel to said rows, drivingmeans for reciprocating said carriage, a first circuit for controllingsaid driving means, two sets of brushes mounted on said carriage, eachset being arranged for cooperation with the terminal pins of one of saidgroups, and a second circuit to be controlled by said switch. thecombination of said selector switch with a first switching means mountedon said frame for controlling said first circuit, cam means movablymounted on said frame for operating said first switching means, andmeans carried by said carriage for engaging and moving said cam means ateach end of the carriage stroke, whereby the driving means may bestopped at each end of the stroke when the switch is not in use formaking a call; and second switching means having two operating positionsmounted on said frame for connecting said second circuit to either oneor the other of said sets of brushes, and means controlled by thecarriage for causing said second switching means to assume one operatingposition at one end of the stroke of said carriage and the otherposition at the other end of said stroke.

8. The combination of a selector switch with switching means accordingto claim 7, in which the means controlled by the carriage for operatingthe second switching means comprises a bar having projections at the endthereof mounted on said frame parallel to the path of the carriage andarranged for limited longitudinal movement with respect to said frameand an arm carried by said carriage and adapted to engage said projections for shifting said bar at each end of the carriage movement.

9. The combination of a selector switch with switching means accordingto claim 7 in which the cam means comprises a bail pivotally mounted onthe frame on an axis parallel to the path of the carriage and having camsurfaces at the ends of said bail, a cam arm carried by said carriagefor engaging said cam surfaces, and an arm on said bail for operatingthe first switching means when the bail is rocked about its pivot.

- GERALD DEAKIN.

I REFERENCES. CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Name Date 2,240,039 Hickman Apr. 29, 19412,330,812 Deakin Oct. 5, 1943 2,346,912 Deakin Apr. 18, 1944

